In bitcoin, when a transaction is under-priced and stuck unconfirmed on the blockchain, it is possible to bump it by setting up a CPFP transaction. Is there a similar way to achieve this in Ethereum? Say, transaction #1 has gas price set to 5Gwei and nobody is picking it up. Can I set up a transaction #2 whose code is something like "execute transaction #1 first" and price it at 10Gwei? How could this be achieved?

2 Answers 2


You can just resend the same transaction with the same nonce with a higher gas price. Two transactions with the same nonce can't be mined, so miners will mine the better one


Just to add a bit more background to the accepted answer here, yes, the normal way this is handled in Ethereum is by resending the same transaction (same nonce) with a higher gas price. This is known as "replace-by-fee." CPFP is much harder in Ethereum than in Bitcoin because of the power and expressivity of transactions and Ethereum's VM. For one thing, for any transaction that's not a simple value transfer, it's not possible to know with any certainty exactly how much gas a "child" transaction will pay without actually executing the transaction (and even then, it can change, depending on the block it's mined into and the state at the time it's executed). It adds a lot of complexity, and several DoS attack vectors, to client implementations.

There's lots more information from Peter Szilagy in this thread.

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